JP4170110B2 - Liquid crystal display device and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid crystal display device that displays using external incident light and a manufacturing method thereof.
[0002]
[Prior art]
Conventionally, a thin film transistor is known as a thin film laminated device used in a liquid crystal display device. By mounting the thin film transistor as a switching element in an active matrix liquid crystal display device, high-speed moving images and fine display, which are performances that can be obtained by the liquid crystal display device, can be performed. Note that an active matrix liquid crystal display device is a device in which a switching element is provided for each pixel to control charges applied to the pixel electrode.
[0003]
The liquid crystal display device using the above-described thin film transistor can withstand heat treatment, chemicals, and the like when forming the thin film transistor by using a glass substrate or a quartz substrate as a substrate.
[0004]
In particular, in recent years, in portable information terminals, for which demand is increasing, liquid crystal display devices using thin film transistors are mounted. By using a reflective liquid crystal display device as a liquid crystal display device used for a portable information terminal, a backlight is unnecessary and low power consumption can be realized.
[0005]
Note that a reflective liquid crystal display device includes a first insulating substrate having a scanning wiring, a signal wiring, a thin film transistor, and a reflective electrode in a grid pattern, a transparent filter having a color filter layer, a black matrix, and a counter electrode. A liquid crystal display device is formed by bonding two insulating substrates facing each other and injecting a twisted nematic (TN) liquid crystal between the two substrates.
[0006]
Thus, liquid crystal display devices using thin film transistors are applied to various fields, and their required performance is diversified. In particular, as the performance required for the liquid crystal display device, since the demand for the liquid crystal display device in the portable information terminal is increasing as described above, it is important to reduce the weight, improve the impact resistance, or reduce the cost. Is being viewed.
[0007]
However, in a conventional liquid crystal display device in which a thin film transistor is formed on a glass substrate or a quartz substrate, there is a limit to reducing the thickness of the substrate itself. In addition, if the thickness of the glass substrate or the quartz substrate is reduced in order to reduce the weight of the liquid crystal display device, the substrate is easily broken and weakened against impact. Furthermore, due to the cost required for the glass substrate and the quartz substrate, there is a limit to the cost reduction of the liquid crystal display device.
[0008]
That is, it is difficult for a thin film transistor using an existing glass substrate or the like to realize weight reduction, improved impact resistance, or cost reduction as performance required for a liquid crystal display device.
[0009]
In order to realize weight reduction, impact resistance improvement, and cost reduction in such a liquid crystal display device, attempts have been made to form thin film transistors using a plastic substrate.
[0010]
However, the conventional reflective liquid crystal display device has the following problems.
[0011]
That is, in the conventional reflective liquid crystal display device, when the first insulating substrate having a thin film transistor and the second insulating substrate having a color filter layer are bonded together, light leakage and color bleeding due to misalignment of the bonding are performed. In order to prevent this, accurate bonding is essential.
[0012]
Therefore, a color filter layer-on-array structure in which a color filter layer and a thin film transistor are formed on the same insulating substrate is disclosed in Japanese Patent Laid-Open No. 2000-162625 (published on June 16, 2000) and Japanese Patent Laid-Open No. 2000-187209. It is disclosed in the gazette (published July 4, 2000).
[0013]
According to the method described in the above publication, since the color filter layer can be formed on the substrate having the thin film transistor, the first insulating substrate having the thin film transistor is bonded to the second insulating substrate having the color filter layer. Thus, a liquid crystal display device can be formed without taking into account the positional deviation.
[0014]
[Patent Document 1]
JP 2000-162625 A (released on June 16, 2000)
[0015]
[Patent Document 2]
JP 2000-187209 A (published July 4, 2000)
[0016]
[Problems to be solved by the invention]
However, when a plastic substrate is used as the insulating substrate, the plastic substrate expands and contracts due to a moisture and heat process in a process of forming a color filter layer or a process of forming a pixel electrode.
[0017]
That is, in the technique disclosed in the above publication, when a plastic substrate is used as the insulating substrate, it is difficult to accurately align the color filter layer on the reflective electrode on the substrate, resulting in misalignment. This misalignment causes light leakage and color blurring, which degrades the display image quality.
[0018]
That is, in the conventional reflective liquid crystal display device, there is a problem that it is difficult to achieve both cost reduction using a plastic substrate and prevention of deterioration of display image quality. .
[0019]
The present invention has been made in view of the above-described conventional problems, and its object is to realize weight reduction, improvement in impact resistance, and cost reduction, and display caused by expansion and contraction of the substrate. It is an object of the present invention to provide a liquid crystal display device capable of preventing deterioration of image quality and a manufacturing method thereof.
[0020]
[Means for Solving the Problems]
In order to solve the above problems, a liquid crystal display device of the present invention is formed on a reflective electrode formed on an upper side of a substrate, a color filter layer formed on the reflective electrode, and an upper side of the color filter layer. In addition, a transparent electrode electrically connected to the reflective electrode is provided at the peripheral edge of the color filter layer.
[0021]
In addition, in order to solve the above problems, the method for manufacturing a liquid crystal display device according to the present invention forms a reflective electrode on the upper side of the substrate, forms a color filter layer on the reflective electrode, and surrounds the periphery of the color filter layer. A transparent electrode is formed above the color filter layer so as to be electrically connected to the reflective electrode in the portion.
[0022]
According to the said structure, a reflective electrode and a transparent electrode are electrically connected in the peripheral part of a color filter layer. Therefore, even if a positional shift occurs due to the expansion and contraction of the substrate in the color filter layer forming step, the electrical connection between the reflective electrode and the transparent electrode can be ensured.
[0023]
As a result, a liquid crystal display device that can achieve a reduction in weight, an improvement in impact resistance, and a reduction in cost by using a plastic substrate as a substrate, and can prevent deterioration in display image quality due to expansion and contraction of the substrate. Can be provided.
[0024]
Further, in order to solve the above problems, the liquid crystal display device of the present invention is the liquid crystal display device having the above structure, wherein the distance from the side end of the reflective electrode to the side end of the color filter layer is the color filter layer and It is determined based on the amount of expansion and contraction of the substrate in the step of forming the transparent electrode.
[0025]
According to another aspect of the present invention, there is provided a method for manufacturing a liquid crystal display device, wherein the distance from the side end of the reflective electrode to the side end of the color filter layer is set to It is determined based on the amount of expansion and contraction of the substrate in the step of forming the layer and the transparent electrode.
[0026]
According to the above configuration, the distance from the side edge of the reflective electrode to the side edge of the color filter layer is determined based on the amount of expansion / contraction of the substrate in the step of forming the color filter layer and the transparent electrode. Therefore, the side of the color filter layer from the side edge of the reflective electrode is determined based on the larger one of the amount of expansion / contraction of the substrate in the step of forming the color filter layer and the amount of expansion / contraction of the substrate in the step of forming the transparent electrode. The distance to the edge can be determined.
[0027]
That is, even when a plastic substrate is used as the substrate, the distance from the side edge of the reflective electrode to the side edge of the color filter layer is determined by the amount of positional deviation between the reflective electrode and the color filter layer accompanying the expansion and contraction of the substrate, and the reflective electrode. It can be set larger than the amount of positional deviation from the transparent electrode.
[0028]
That is, it is possible to redundantly design the color filter layer with a margin that can be tolerated with respect to the positional deviation due to the expansion and contraction of the substrate. Therefore, the color filter layer can be aligned on the reflective electrode without being displaced. Therefore, it is possible to prevent the positional deviation between the reflective electrode and the color filter layer and the positional deviation between the reflective electrode and the transparent electrode.
[0029]
As a result, a liquid crystal display device that can achieve a reduction in weight, an improvement in impact resistance, and a reduction in cost by using a plastic substrate as a substrate, and can prevent deterioration in display image quality due to expansion and contraction of the substrate. Can be provided.
[0030]
In order to solve the above problems, the liquid crystal display device of the present invention has a plurality of pixels arranged in a matrix in the liquid crystal display device having the above structure, and the reflective electrode corresponds to the plurality of pixels. A plurality of color filter layers are formed, and the color filter layer is formed so as to overlap with a plurality of reflective electrodes adjacent in the row direction or column direction of the plurality of pixels. Alternatively, a plurality of the reflective electrodes are formed in a matrix on the upper side of the substrate, and the color filter layer covers the reflective electrodes adjacent in the row direction or the column direction in the matrix of the reflective electrodes. It may be characterized by being formed as described above.
[0031]
According to the said structure, the reflective electrode of many areas can be covered with a color filter layer. Therefore, the effective pixel area of the pixel electrode composed of the reflective electrode and the transparent electrode can be increased. The “effective pixel area” is an area displayed as one pixel, and specifically refers to a projected area of the color filter layer onto the reflective electrode. Thereby, the quality of a display image can be improved more.
[0032]
In order to solve the above problems, the liquid crystal display device of the present invention is such that the color filter layer is formed on the reflective electrode in a pattern smaller than the reflective electrode. It is characterized by.
[0033]
According to the above configuration, the color filter layer is formed on the reflective electrode in a pattern smaller than the reflective electrode. Therefore, the reflective electrode and the transparent electrode can be patterned with the same mask.
[0034]
Thereby, the manufacturing cost of a liquid crystal display device can be reduced.
[0035]
In order to solve the above problems, the liquid crystal display device of the present invention is characterized in that the substrate is a plastic substrate in the liquid crystal display device having the above structure.
[0036]
The plastic substrate has a considerably larger amount of expansion and contraction in the color filter layer forming step than the glass substrate. Therefore, according to the said structure, the position shift by the expansion / contraction of the plastic substrate by a water | moisture content or a heat process at the time of forming a color filter layer on the reflective electrode on a plastic substrate can be prevented. For this reason, it is possible to prevent a color filter layer from overlapping colors and pixels from overlapping, and to realize a liquid crystal display device free from color bleeding.
[0037]
The method for manufacturing a liquid crystal display device according to the present invention is characterized in that, in the method for manufacturing a liquid crystal display device having the above-described configuration, the reflective electrode and the transparent electrode are patterned using the same mask.
[0038]
According to the above configuration, the reflective electrode and the transparent electrode are patterned using the same mask. Thereby, the manufacturing cost of a liquid crystal display device can be reduced.
[0039]
DETAILED DESCRIPTION OF THE INVENTION
[Embodiment 1]
An embodiment of the present invention will be described below with reference to FIGS.
[0040]
As shown in FIG. 1, an active matrix substrate 1 used in the liquid crystal display device of the present embodiment includes a plastic substrate (substrate) 2, an inorganic material layer 3, a gate electrode 4, a gate insulating film 5, and an intrinsic semiconductor. The film 6, the conductive semiconductor film 7, the source electrode 8, the drain electrode 9, the channel portion 10, the protective insulating film 11, the interlayer insulating film 12, the reflective electrode 13, the color filter layer 14, and the transparent And an electrode 15.
[0041]
The plastic substrate 2 has a thickness of about 0.2 mm and is made of polyethersulfone. The plastic substrate 2 may be transparent or opaque as long as it has heat resistance to the maximum temperature in the process of forming the active matrix substrate 1. The plastic substrate 2 is not limited to polyether sulfone, and may be a resin such as polyethylene terephthalate, polyarylate, polycarbonate, polyethylene, polymethyl methacrylate, polyimide, or epoxy resin.
[0042]
The inorganic material layer 3 has a thickness of about 1500 mm, and Si _x N _y Consists of. Further, the inorganic material layer 3 has three effects: (1) the effect of improving the adhesion of the gate wiring (scanning wiring) formed on the inorganic material layer 3, and (2) the display characteristics of the liquid crystal display device. There are effects of preventing impurities and gases from permeating through the plastic substrate 2 and (3) an effect of minimizing the expansion and contraction of the plastic substrate 2 due to moisture.
[0043]
The inorganic material layer 3 is made of Si. _x N _y Without being limited thereto, it can be formed of an insulating material. For example, SiO _x , Si: O: N, Si: O: H, Si: N: H, Si: O: N: H, Si _Three N _Four Etc.
[0044]
The gate electrode 4 has a thickness of about 2000 mm and is made of a metal such as aluminum (Al). The gate insulating film 5 is formed on the gate electrode 4 and is made of SiN. _x Consists of.
[0045]
The intrinsic semiconductor film 6 is formed on the gate electrode 4 with the gate insulating film 5 interposed therebetween, is made of a non-doped a-Si film, and is formed in an island pattern.
[0046]
The conductive semiconductor film 7 is formed on the intrinsic semiconductor film 6 and is n doped with phosphorus. ⁺ It consists of a type a-Si film. Further, the conductive semiconductor film 7 is separated by the channel portion 10 on the intrinsic semiconductor film 6.
[0047]
On the separated conductive semiconductor film 7, a source electrode 8 and a drain electrode 9 made of a Ti film are formed.
[0048]
The protective insulating film 11 is formed on the source electrode 8 and the drain electrode 9. The interlayer insulating film 12 is formed on the protective insulating film 11 and is made of an acrylic photosensitive resin.
[0049]
The reflective electrode 13 is made of a metal such as Al, and is formed on the interlayer insulating film 12. The color filter layer 14 is formed by dispersing a pigment in an acrylic resin, and is formed on the reflective electrode 13.
[0050]
Further, the transparent electrode 15 is formed so as to cover the color filter layer 14 and is a transparent conductive film made of ITO (Indium Tin Oxide). Further, the peripheral edge of the transparent electrode 15 is electrically connected to the reflective electrode 13. Note that an alignment film (not shown) made of polyimide resin is formed on the transparent electrode 15.
[0051]
Next, the counter substrate 20 which is another substrate used in the liquid crystal display device of the present embodiment will be described. As shown in FIG. 1, the counter substrate 20 used in the liquid crystal display device of the present embodiment is disposed so as to face the active matrix substrate 1, and includes a plastic substrate 21 and a counter electrode 22.
[0052]
The plastic substrate 21 has a thickness of about 0.2 mm and is made of polyethersulfone. The material of the plastic substrate 21 is not limited to polyether sulfone, and may be a transparent resin such as polyethylene terephthalate, polyarylate, polycarbonate, polyethylene, polymethyl methacrylate, polyimide, and epoxy resin.
[0053]
The counter electrode 22 is formed on the plastic substrate 21 and is a transparent conductive film made of ITO (Indium Tin Oxide). Note that an alignment film (not shown) made of polyimide is formed on the counter electrode 22.
[0054]
The active matrix substrate 1 and the counter substrate 20 having the above-described configuration are bonded to each other via a sealant provided at the peripheral edge of a region where the reflective electrode 13 and the transparent electrode 15 are formed in the active matrix substrate 1. Further, the liquid crystal display device of the present embodiment is formed by filling the liquid crystal 23 between the active matrix substrate 1 and the counter substrate 20.
[0055]
Next, the planar structure of the active matrix substrate 1 having the above configuration will be described. As shown in FIG. 2, the active matrix substrate 1 is provided with a plurality of gate wirings 4 a connected to the plurality of gate electrodes 4 and auxiliary capacitance wirings 16.
[0056]
A source wiring 8 a connected to the plurality of source electrodes 8 is provided on the active matrix substrate 1.
[0057]
The gate wiring 4a and the source wiring 8a are orthogonal to each other via a gate insulating film 5 (not shown). Further, the auxiliary capacitance line 16 is provided orthogonal to the source line 8a.
[0058]
The drain electrode 9 is formed so as to extend onto the auxiliary capacitance line 16 and overlaps the auxiliary capacitance line 16 with the inorganic material layer 3 interposed therebetween. Thereby, the drain electrode 9 forms an auxiliary capacitance.
[0059]
The reflective electrode 13 is electrically connected to the drain electrode 9 through contact holes 17 and 18 provided in the protective insulating film 11 (FIG. 1) and the interlayer insulating film 12 (FIG. 1), respectively.
[0060]
By configuring the gate electrode 4, the gate wiring 4a, the source electrode 8, and the source wiring 8a as described above, a thin film transistor as a switching element is formed. An interlayer insulating film 12 (FIG. 1) is formed on the thin film transistor.
[0061]
Further, the color filter layer 14 is formed so as to extend along the direction in which the source wiring 8a is disposed and straddle the region where the reflective electrode 13 and the transparent electrode 15 are formed.
[0062]
The width of the color filter layer 14 is formed smaller than the width of the pixel electrode composed of the reflective electrode 13 and the transparent electrode 15. Specifically, the left and right ends of the color filter layer 14 are formed so as to form an interval of the alignment margin δx from the left and right ends of the pixel electrode, respectively. The alignment margin δx is the distance from the edge of the reflective electrode 13 to the edge of the color filter layer 14. A method for setting the alignment margin δx will be described later.
[0063]
Thereby, the transparent electrode 15 can be electrically connected to the reflective electrode 13 at the left and right ends of the color filter layer 14.
[0064]
Next, an example of a method for manufacturing the liquid crystal display device of the present embodiment will be described below.
[0065]
First, on a plastic substrate 2 made of polyethersulfone having a length of 360 mm, a width of 465 mm, and a thickness of 0.2 mm, _x N _y The inorganic material layer 3 made of, for example, is formed by sputtering at a film forming temperature of 190 ° C. so that the film thickness becomes 1500 mm. Note that the film formation temperature when forming the inorganic material layer 3 needs to be lower than the temperature at which the plastic substrate 2 is thermally deformed.
[0066]
Next, a metal film such as Al is formed on the inorganic material layer 3 by a sputtering method at a film formation temperature of 190 ° C. so that the film thickness becomes 2000 mm. Thereafter, through the photolithography process and the patterning process, the gate wiring 4a and the gate electrode 4 connected thereto are formed. The metal film is not limited to Al, and may be formed using an Al alloy, Ta, TaN / Ta / TaN, or Ti / Al / Ti.
[0067]
Next, SiN is formed on the gate electrode 4 and the gate wiring 4a by plasma CVD (Chemical Vapor Deposition). _x A gate insulating film 5 is formed at a film forming temperature of 220 ° C.
[0068]
Subsequently, an intrinsic semiconductor film 6 made of a non-doped a-Si film or the like, and n doped with phosphorus by plasma CVD. ⁺ A conductive semiconductor film 7 made of a type a-Si film or the like is continuously laminated at a deposition temperature of 220 ° C. by plasma CVD. Thereafter, the intrinsic semiconductor film 6 is patterned into an island shape by a photolithography process and a patterning process, thereby forming a semiconductor layer.
[0069]
Next, a Ti film, which is a conductive metal film, is deposited on the surface of the gate insulating film 5 including the semiconductor layer and the gate electrode 4 at a film forming temperature of 28 ° C. by sputtering. Thereafter, the source wiring 8a, the source electrode 8, and the drain electrode 9 are formed by a photolithography process. The material for forming the source wiring 8a, the source electrode 8, and the drain electrode 9 is not limited to Ti, but can be Mo, Al / Ti, or Ag.
[0070]
Next, using the source electrode 8 and the drain electrode 9 made of Ti as a mask, n ⁺ The upper part of the mold a-Si film and the a-Si film is removed by patterning to form the channel portion 10.
[0071]
Subsequently, SiN is used as the protective insulating film 11. _x Are stacked at a film forming temperature of 220 ° C. by plasma CVD. Thereafter, a contact hole 17 corresponding to the drain electrode 9 is formed in the protective insulating film 11 by a photolithography process.
[0072]
Next, an interlayer insulating film 12 made of an acrylic photosensitive organic resin is applied on the protective insulating film 11, and a contact hole 18 corresponding to the drain electrode 9 is formed in the interlayer insulating film 12 by a photolithography process.
[0073]
Next, an Al film is laminated on the interlayer insulating film 12 by a sputtering method at a heating temperature of 100 ° C. and a pressure of 0.1 Pa so that the film thickness becomes 1500 mm. Thereafter, the reflective electrode 13 is patterned by photolithography. The reflective electrode 13 is not limited to Al, and may be patterned using Ag or an Ag alloy.
[0074]
In the present embodiment, as shown in FIG. 3A, the reflective electrode 13 and the transparent electrode 15 are patterned in separate steps so that the pattern of the reflective electrode 13 is the same pattern as the transparent electrode 15. The
[0075]
However, as shown in FIG. 3B, the reflective electrode 13 may be patterned only in the direction in which the gate wiring 4a is disposed.
[0076]
Thereby, when patterning the transparent electrode 15 to be formed later, the reflective electrode 13 and the transparent electrode 15 can be simultaneously patterned in the direction in which the source wiring 8a is disposed using the same mask.
[0077]
Next, the color filter layer 14 is formed on the reflective electrode 13. Specifically, first, a resist containing a red (R) pigment is applied, and the color filter layer pattern R is formed by photolithography. Thereafter, by baking at 200 ° C., the color filter layer pattern is heated and the inclination of the edge portion of the color filter layer is made gentle.
[0078]
As described above, by gently sloping the edge portion of the color filter layer, it is possible to prevent a transparent electrode 15 (described later) from being cut off due to a step in the color filter layer and a domain from being caused by a liquid crystal molecular light distribution failure.
[0079]
That is, when the color filter layer has a vertical inclination (inclination angle of 90 °), the liquid crystal molecules are not normally aligned in the stepped portion, and light leakage occurs in the poorly aligned portion. Therefore, by smoothing the inclination, the liquid crystal molecules can be prevented from being disturbed and light leakage can be prevented.
[0080]
Similarly, a resist containing green (G) and blue (B) pigments is applied, patterning is performed by a photolithography method, and color filter layer patterns G and B are formed by a baking process.
[0081]
At this time, as shown in FIG. 3A, the pattern of the color filter layer 14 is formed so as to extend in the direction in which the source wiring 8 a is disposed and to straddle the plurality of reflective electrodes 13. Therefore, the effective pixel area of the pixel electrode composed of the reflective electrode 13 and the transparent electrode 15 can be increased.
[0082]
Further, the pattern of the color filter layer 14 is formed with a narrower width than the width of the reflective electrode 13. That is, the width of the color filter layer 14 is designed to be smaller than the width of the reflective electrode 13 by the alignment margin δx.
[0083]
As shown in FIG. 4, the color filter layer 14 may be formed with a dot pattern smaller than the pixel electrode composed of the transparent electrode 15 and the reflective electrode 13. Thereby, the pixel electrode which consists of the reflective electrode 13 and the transparent electrode 15 can be patterned with the same mask, and reduction of manufacturing cost can be aimed at.
[0084]
Subsequently, ITO or the like is laminated on the color filter layer 14 by sputtering, and a plurality of transparent electrodes 15 as pixel electrodes are formed by photolithography. At this time, the color filter layer 14 is sandwiched between the transparent electrode 15 and the reflective electrode 13. Thereby, the transparent electrode 15 is electrically connected to the reflective electrode 13 at both ends of the color filter layer 14.
[0085]
Next, a transparent electrode is laminated as a counter electrode 22 by sputtering on a transparent plastic substrate 21 such as polyether sulfone having a thickness of 0.2 mm as the counter substrate 20.
[0086]
Thereafter, the manufactured active matrix substrate 1 and the counter substrate 20 are bonded and bonded using an adhesive sealing material. A liquid crystal display device is formed by filling a liquid crystal 23, for example, a TN liquid crystal, in a gap between both substrates.
[0087]
By following the above procedure, the liquid crystal display device of the present embodiment can be manufactured.
[0088]
Next, the alignment margin δx, which is a feature point of the liquid crystal display device of the present embodiment, will be described. The alignment margin δx is set to a value larger than the product of the largest value of the following values (1) to (4) and the substrate size. The values of (1) to (4) are
(1) Amount of expansion / contraction of the plastic substrate 2 from the formation of the reflective electrode 13 described later to the step of forming the R (red) color filter layer
(2) Amount of expansion / contraction of the plastic substrate 2 from the formation of the reflective electrode 13 to the step of forming the G (green) color filter layer
(3) Amount of expansion / contraction of the plastic substrate 2 from the formation of the reflective electrode 13 to the process of forming the B (blue) color filter layer
(4) Expansion amount of the plastic substrate 2 from the formation of the reflective electrode 13 to the formation of the transparent electrode 15 (pixel electrode)
It is. The expansion / contraction amount of the plastic substrate 2 is the distance from the center to the end of the plastic substrate 2 before processing, which is the amount of change in the distance from the center to the end of the plastic substrate 2 before and after processing with respect to the reflective electrode. The ratio to.
[0089]
In this embodiment, the values (1) to (4) were 45 ppm, 55 ppm, 50 ppm, and 60 ppm, respectively, and the value (4) was the maximum. On the other hand, the size of the substrate is 360 × 465 mm as described above. Therefore, the product of the value of (4) and the substrate size is obtained as follows.
[0090]
232.5 mm (distance from substrate edge to substrate center) x 10 ^Three μm × 60ppm ÷ 10 ⁶ = 13.95 (μm)
Therefore, the alignment margin δx is set to 15 μm.
[0091]
The reason for setting the alignment margin δx in this way will be described below.
[0092]
That is, if the substrate is a plastic substrate in the heating process and the cleaning process included in the process from the formation of the reflective electrode 13 to the formation of the transparent electrode 15, the amount of expansion / contraction of the substrate increases. When the substrate expands and contracts, there may be a positional shift between the reflective electrode 13 and the color filter layer 14 and a positional shift between the reflective electrode 13 and the transparent electrode 15. Due to such a displacement, the effective pixel area may change and image quality may deteriorate.
[0093]
However, if the alignment margin δx is set as described above, the alignment margin δx is determined by the amount of positional deviation between the reflective electrode 13 and the color filter layer 14 due to the expansion and contraction of the plastic substrate 2, and between the reflective electrode 13 and the transparent electrode 15. It is set to be larger than the displacement amount. That is, the color filter layer 14 can be accurately aligned on the reflective electrode 13. Therefore, it is possible to prevent the positional deviation between the reflective electrode 13 and the color filter layer 14 and the positional deviation between the reflective electrode 13 and the transparent electrode 15.
[0094]
Further, by preventing displacement, the transparent electrode 15 and the reflective electrode 13 can be reliably kept in electrical connection over the entire surface of the active matrix substrate 1. Thereby, display quality can also be improved.
[0095]
As described above, the liquid crystal display device according to the present embodiment includes the reflective electrode 13 formed on the upper side of the plastic substrate 2, the color filter layer 14 formed on the reflective electrode 13, and the peripheral portion of the color filter layer 14. A transparent electrode 15 electrically connected to the reflective electrode 13 is provided, and a distance δx from the side end of the reflective electrode 13 to the side end of the color filter layer 14 forms the color filter layer 14 and the transparent electrode 15. It is determined based on the amount of expansion / contraction of the plastic substrate 2 in the process.
[0096]
Further, in the manufacturing method of the liquid crystal display device according to the present embodiment, the reflective electrode 13 is formed on the upper side of the plastic substrate 2, the color filter layer 14 is formed on the reflective electrode 13, and the peripheral edge of the color filter layer 14 is formed. The transparent electrode 15 electrically connected to the reflective electrode 13 is formed on the color filter layer 14, while the distance δx from the side edge of the reflective electrode 13 to the side edge of the color filter layer 14 is set to the color filter layer 14 and transparent color. This is a method of determining based on the amount of expansion / contraction of the plastic substrate 2 in the step of forming the electrode 15.
[0097]
According to the above configuration, the distance from the side edge of the reflective electrode 13 to the side edge of the color filter layer 14 is determined based on the amount of expansion / contraction of the plastic substrate 2 in the process of forming the color filter layer 14 and the transparent electrode 15. Yes. Therefore, the side of the reflective electrode 13 is determined based on the larger value of the expansion / contraction amount of the plastic substrate 2 in the step of forming the color filter layer 14 and the expansion / contraction amount of the plastic substrate 2 in the step of forming the transparent electrode 15. A distance δx from the end to the side end of the color filter layer 14 can be determined.
[0098]
That is, the distance δx from the side edge of the reflective electrode 13 to the side edge of the color filter layer 14 is set to the amount of positional deviation between the reflective electrode 13 and the color filter layer 14 due to the expansion and contraction of the plastic substrate 2, and the reflective electrode 13 and the transparent electrode. It can be set to be larger than the amount of positional deviation from 15. That is, the color filter layer 14 can be accurately aligned on the reflective electrode 13. Therefore, it is possible to prevent the positional deviation between the reflective electrode 13 and the color filter layer 14 and the positional deviation between the reflective electrode 13 and the transparent electrode 15.
[0099]
This makes it possible to reduce the weight, improve the impact resistance, and reduce the cost by using a plastic substrate as the substrate, and to prevent the display image from deteriorating due to the expansion and contraction of the plastic substrate 2. .
[0100]
In the liquid crystal display device according to the present embodiment, a plurality of the reflective electrodes 13 are formed in a matrix on the upper side of the plastic substrate 2, and the color filter layer 14 is arranged in the row direction in the matrix of the reflective electrodes 13 or It is formed so as to cover a plurality of reflective electrodes 13 adjacent in the column direction.
[0101]
According to the above configuration, the reflective electrode 13 having a large area can be covered with the color filter layer 14. Therefore, the effective pixel area of the pixel electrode composed of the reflective electrode 13 and the transparent electrode 15 can be increased. Thereby, the quality of a display image can be improved more.
[0102]
As one of the liquid crystal display devices of this embodiment, the color filter layer 14 is formed on the reflective electrode 13 with a pattern smaller than the reflective electrode 13.
[0103]
According to the above configuration, the color filter layer 14 is formed on the reflective electrode 13 in a pattern smaller than the reflective electrode 13. Therefore, the reflective electrode 13 and the transparent electrode 15 can be patterned with the same mask. Thereby, the manufacturing cost of a liquid crystal display device can be reduced.
[0104]
Moreover, the manufacturing method of the liquid crystal display device of this Embodiment is the method of patterning the reflective electrode 13 and the transparent electrode 15 with the same mask.
[0105]
According to the above configuration, the reflective electrode 13 and the transparent electrode 15 are patterned using the same mask. Thereby, the manufacturing cost of a liquid crystal display device can be reduced.
[0106]
[Embodiment 2]
Hereinafter, other embodiments of the liquid crystal display device of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the following embodiment, and the feature points of the first embodiment and the feature points of the second embodiment can be combined as appropriate.
[0107]
First, the structure of the liquid crystal display device according to the embodiment of the present invention will be described with reference to FIGS. Note that the liquid crystal display device has a plurality of pixel regions arranged in a matrix.
[0108]
In this specification, an area of the liquid crystal display device corresponding to a “pixel” that is a minimum unit of display is referred to as a “pixel area”. In an active matrix liquid crystal display device, a pixel region is defined by a pixel electrode and a counter electrode facing the pixel electrode. On the other hand, in a simple matrix liquid crystal display device, a pixel region is defined by an intersection of a striped column electrode (signal electrode) and a row electrode (scanning electrode).
[0109]
As shown in FIG. 5, the liquid crystal display device includes an active matrix substrate (hereinafter referred to as “TFT substrate”) 40 and a counter substrate 50 facing each other, and a liquid crystal layer 60 provided therebetween. Yes.
[0110]
The TFT substrate 40 includes a TFT (thin film transistor) 11 as a switching element, a reflective electrode 44, a color filter layer 45 formed on the reflective electrode 44, and a transparent formed on the color filter layer 45 in each pixel region. Electrode 46.
[0111]
The configuration of the TFT substrate 40 will be described in more detail below. The TFT substrate 40 has an insulating substrate 32, and a gate wiring 33, a gate electrode 33 a, an auxiliary capacitance wiring 47, and the like are formed on the insulating substrate 32. Further, a gate insulating film 34 is formed so as to cover them. An intrinsic semiconductor layer 35, a conductive semiconductor layer 36, a source electrode 37a and a drain electrode 38 are formed on the gate insulating film 34 located on the gate electrode 33a, and these constitute the TFT 41.
[0112]
Note that the gate electrode 33 a of the TFT 41 is electrically connected to the gate wiring 33, the source electrode 37 a is electrically connected to the source wiring 37, and the drain electrode 38 is electrically connected to the reflective electrode 44. The conductive semiconductor layer 36 is formed on the intrinsic semiconductor layer 35 and is separated by the channel portion 9.
[0113]
A protective insulating film 42 is formed so as to cover the TFT 41, and an interlayer insulating film 43 is formed on the protective insulating film 42 so as to cover almost the entire surface of the insulating substrate 32.
[0114]
A reflective electrode 44 is formed on the interlayer insulating film 43. In the liquid crystal display device of the present embodiment, the reflective electrode 44 includes a metal layer 44a and a transparent conductive layer 44b formed on the metal layer 44a, as shown in FIG. The metal layer 44a of the reflective electrode 44 is in contact with the drain electrode 38 in contact holes 42a and 43a (see FIG. 6) formed in the protective insulating film 42 and the interlayer insulating film 43. The TFT 41 is electrically connected.
[0115]
A color filter layer 45 is formed on the transparent conductive layer 44 b of the reflective electrode 44 so as to cover the reflective electrode 44. The color filter layer 45 is typically a red layer, a green layer, or a blue layer.
[0116]
A transparent electrode 46 is formed on the color filter layer 45 so as to cover the color filter layer 45.
[0117]
As illustrated in FIG. 5, the counter substrate 50 includes a transparent insulating substrate 51 and a counter electrode 52 formed on the transparent insulating substrate 51. The counter electrode 52 is, for example, a single solid electrode provided in common for a plurality of pixels, and is a transparent electrode made of ITO (indium tin oxide) or the like.
[0118]
The above-described TFT substrate 40 and the counter substrate 50 are bonded to each other through a sealing material provided around a display area including a plurality of pixel areas. Although not shown here, an alignment film made of polyimide resin or the like is formed on the surface of the TFT substrate 40 and the counter substrate 50 on the liquid crystal layer 60 side.
[0119]
The liquid crystal display device having the above-described configuration is a reflective liquid crystal display device that performs display using light incident from the counter substrate 50 side and reflected by the reflective electrode 44. Ambient light (external light) incident from the counter substrate 50 side passes through the liquid crystal layer 60, is reflected by the reflective electrode 44, passes through the liquid crystal layer 60 again, and is emitted from the counter substrate 50. The emitted light is modulated by the liquid crystal layer 60. Thereby, image display is performed.
[0120]
Next, a method for manufacturing a liquid crystal display device will be described.
[0121]
First, the TFT substrate 40 is manufactured as follows. That is, an insulating substrate 32 is prepared, and a plurality of TFTs 41 are formed on the insulating substrate 32. The step of forming the TFT on the insulating substrate 32 can be performed by a known method using a known material.
[0122]
For example, first, a metal film made of Al is formed on an insulating substrate 32 made of glass by a sputtering method so as to have a thickness of about 200 nm, and then the metal film is formed by a photolithography process and patterning. By patterning, the gate wiring 33, the gate electrode 33a, and the auxiliary capacitance wiring 47 are formed. The material of the metal film is not limited to Al, and Al alloy, Ta, TaN / Ta / TaN, Ti / Al / Ti, or the like may be used.
[0123]
Next, SiN is formed on the gate wiring 33, the gate electrode 33a, and the auxiliary capacitance wiring 47 by using a plasma CVD method. _x A gate insulating film 34 made of is formed.
[0124]
Subsequently, a non-doped a-Si film and n doped with phosphorus are formed on the gate insulating film 34 using a plasma CVD method. ⁺ A type a-Si film is continuously deposited, and then patterned into an island shape by a photolithography process and patterning to form an intrinsic semiconductor layer 35 and a conductive semiconductor layer 36.
[0125]
Further, a metal film made of Ti is formed on the gate insulating film 34 on which the intrinsic semiconductor layer 35 and the conductive semiconductor layer 36 are formed by a sputtering method, and then the metal film is formed by a photolithography process and patterning. Thus, the source wiring 37, the source electrode 37a, and the drain electrode 38 are formed. The material of the metal film is not limited to Ti, and Mo, Al / Ti, Ag, or the like may be used.
[0126]
Next, by using the source electrode 37a and the drain electrode 38 as a mask, the conductive semiconductor layer 36 and the upper portion of the intrinsic semiconductor layer 35 are removed by patterning to form the channel portion 39.
[0127]
Subsequently, SiN is formed on the source electrode 37a and the drain electrode by using a plasma CVD method. _x Then, a contact hole 42a is formed in a portion of the protective insulating film 42 located on the drain electrode 38 by using a photolithography process.
[0128]
Then, an interlayer photosensitive film 43 is formed by applying an acrylic photosensitive organic resin on the protective insulating film 42, and then a portion located on the drain electrode 38 of the interlayer insulating film 43 using a photolithography process. A contact hole is formed in
[0129]
As described above, the TFT 41 can be formed on the insulating substrate 32. Subsequent steps will be described with reference to FIGS. 7A to 7D and FIGS. 8A to 8D.
[0130]
First, as shown in FIG. 7 (a), a metal layer 44a is formed on a substrate 32 on which an interlayer insulating film 43 is formed, and then a transparent conductive layer 44b is formed on the metal layer 44a. 44 is formed.
[0131]
For example, using a sputtering method at room temperature and a pressure of 0.1 Pa, an Al film as the metal layer 44a is continuously formed with a thickness of 100 nm and an IZO film as the transparent conductive layer 44b is continuously formed with a thickness of 10 nm. A reflective electrode 44 is formed by depositing on 43.
[0132]
IZO is In ₂ O _Three It is a hexagonal layered compound represented by —ZnO (composition ratio 90:10 wt%), and an amorphous film (amorphous film) can be easily obtained by depositing at room temperature using a sputtering method.
[0133]
Next, the color filter layer 45 is formed on the reflective electrode 44. For example, first, as shown in FIG. 7B, a resist layer (here, a negative resist layer) 15 ′ containing a red pigment is formed on the reflective electrode 44. Next, as illustrated in FIG. 7C, the resist layer 45 ′ is exposed through the photomask 70. Subsequently, development is performed using a developer (for example, an aqueous potassium hydroxide solution), followed by baking, whereby a red color filter layer 45 is formed as shown in FIG.
[0134]
Similarly, a green color filter layer 45 can be formed by forming a resist layer containing a green pigment, patterning the resist layer using a photolithography process, and baking the resist layer. The blue color filter layer 45 can be formed in the same manner.
[0135]
As a method for forming the color filter layer 45, a pigment dispersion method, a dyeing method, an ink jet method, a laminating method, or the like can be used.
[0136]
Subsequently, a transparent electrode 46 electrically connected to the reflective electrode 44 is formed on the color filter layer 45. For example, first, as shown in FIG. 8A, a transparent electrode 46 ′ is formed by depositing IZO on the color filter layer 45 by sputtering. The transparent electrode 46 is electrically connected to the reflective electrode 44 at the peripheral edge of the color filter layer 45.
[0137]
Next, as shown in FIG. 8B, the photoresist 72 is applied onto the transparent electrode 46 ′ and the photoresist 72 is exposed through the photomask 74. Subsequently, as shown in FIG. 8C, the photoresist 72 is patterned so as to overlap the color filter layer 45 by performing development.
[0138]
Then, by patterning using the photoresist 72 as a mask, as shown in FIG. 8D, transparent electrodes 46 that are electrically independent for each pixel region are formed.
[0139]
The transparent electrode 46 is electrically connected to the reflective electrode 44 by being in contact with the transparent conductive layer 44 b of the reflective electrode 44 through a contact hole 45 a formed in the color filter layer 45. When patterning the transparent electrode 46, for example, using a mixed solution of phosphoric acid: nitric acid: acetic acid at 40 ° C., the transparent electrode 46, the metal layer 44 a and the transparent conductive layer 44 b constituting the reflective electrode 44, Can be simultaneously patterned with a single mask (here, photoresist 72).
[0140]
In this way, the TFT substrate 40 is formed.
[0141]
The counter substrate 50 can be manufactured by a known method using a known material in the same manner as the counter substrate included in the known active matrix liquid crystal display device. For example, the counter substrate 52 is formed by forming the counter electrode 52 on the transparent insulating substrate 51 made of glass with a thickness of 0.7 mm by forming a transparent electrode (for example, ITO film) by sputtering. The
[0142]
The TFT substrate 40 and the counter substrate 50 thus prepared are bonded together using an adhesive sealing material, and then a liquid crystal material (for example, a known liquid crystal material for TN mode) is injected and sealed into the gap between the two substrates. The liquid crystal display device is completed by stopping and forming the liquid crystal layer 60. An alignment film made of polyimide resin or the like is formed on the surfaces of the TFT substrate 40 and the counter substrate 50 on the liquid crystal layer 60 side as necessary.
[0143]
The liquid crystal display device of the present embodiment manufactured as described above has the following effects.
[0144]
That is, in a reflective liquid crystal display device, aluminum or aluminum alloy having high reflectivity, excellent patternability, and low electrical resistance is often used as a material for a metal layer that functions as a reflective electrode.
[0145]
Since the color filter layer is directly formed on the metal layer functioning as the reflective electrode, if an aluminum layer or an aluminum alloy layer is used as the metal layer and the color filter layer is formed by a photolithography process, the color filter layer is alkaline during development of the color filter layer. The metal layer is eroded by the developer. When the metal layer is corroded in this way, a part of the metal layer is lost, and when the area of the reflective electrode is reduced or the color filter layer itself is lost, the display quality is deteriorated.
[0146]
The transparent electrode formed on the color filter layer is electrically connected to the reflective electrode at the peripheral edge of the color filter layer.
[0147]
However, when an aluminum layer or an aluminum alloy layer is used as the metal layer, these metals are easily oxidized, so that the electrical connection between the transparent electrode and the reflective electrode tends to be insufficient, and the reliability is lowered.
[0148]
However, in the liquid crystal display device of the present embodiment, as shown in FIG. 5, the reflective electrode 44 includes the metal layer 44a and the transparent conductive layer 44b formed on the metal layer 44a. The color filter layer 45 formed on 44 is not directly formed on the metal layer 44a, but is formed on the transparent conductive layer 44b. Therefore, even if the color filter layer 45 is formed using a photolithography process, the erosion of the metal layer 44a by the developer can be suppressed.
[0149]
Therefore, even if a material that is easily eroded by the developer is used as the material of the metal layer 44a, it is possible to suppress deterioration in display quality due to a lack of the metal layer 44a or the lack of the color filter layer 45.
[0150]
Further, the reflective electrode 44 has a transparent conductive layer 44b, and the transparent electrode 46 is electrically connected to the reflective electrode 44 through the transparent conductive layer 44b. Therefore, even when a material that is easily oxidized is used as the material of the metal layer 44a, a satisfactory electrical connection between the transparent electrode 46 and the reflective electrode 44 can be realized, and the reliability as a device is improved.
[0151]
Thus, in the liquid crystal display device of this embodiment, as the material of the metal layer 44a of the reflective electrode 44, aluminum or aluminum alloy having high reflectance, excellent patternability, and low electrical resistance can be suitably used. That is, although aluminum and aluminum alloys are easily oxidized and easily eroded by the developer used in the photolithography process, the liquid crystal display device of this embodiment uses aluminum or an aluminum alloy as described above. In this case, deterioration of display quality and reliability is suppressed.
[0152]
The thickness of the transparent conductive layer 44b formed on the metal layer 44a is preferably 1 nm or more and 20 nm or less from the viewpoint of ease of manufacture and further improvement in display quality. This is because if the thickness of the transparent conductive layer 44b is less than 1 nm, uniform film formation by sputtering may be difficult. Further, if the thickness of the transparent conductive layer 44b exceeds 20 nm, the light transmittance in the low wavelength region may be 80% or less, which may cause a decrease in reflectance and coloring.
[0153]
Further, the transparent conductive layer 44b may be a crystal layer or an amorphous layer (amorphous layer). In particular, when the transparent conductive layer 44b is an amorphous layer, the transparent conductive layer and the metal layer can be simultaneously patterned using an etchant for patterning the metal layer.
[0154]
The transparent electrode 46 may also be a crystal layer or an amorphous layer (amorphous layer). In particular, when the transparent electrode 46 is an amorphous layer, the transparent electrode, the transparent conductive layer, and the metal layer can be simultaneously patterned using an etchant for patterning the metal layer.
[0155]
Furthermore, as a material for the transparent conductive layer 44b and the transparent electrode 46, ITO, IZO, or the like can be used. IZO is deposited by sputtering at room temperature to stably form an amorphous transparent electrode. Therefore, when IZO is used as a material for the transparent conductive layer 44b and the transparent electrode 46, amorphous transparent electrode is used. The conductive layer 44b and the amorphous transparent electrode 46 can be easily obtained.
[0156]
Further, the liquid crystal display device of the present invention may have a configuration in which the color filter layer has a stripe pattern and is formed over the plurality of reflective electrodes.
[0157]
By forming the color filter layer in a stripe pattern and straddling over the plurality of reflective electrodes, the effective pixel area can be increased.
[0158]
In the liquid crystal display device of the present invention, the distance from the edge of the reflective electrode to the edge of the color filter layer is determined by the amount of expansion / contraction of the substrate in the color filter layer forming step and the substrate in the transparent electrode forming step. A configuration in which the larger one of the expansion / contraction amounts is larger than the above-mentioned substrate expansion / contraction amount may be employed.
[0159]
That is, the distance from the edge of the reflective electrode to the edge of the color filter layer is the larger one of the substrate expansion amount in the color filter layer forming step and the substrate expansion amount in the transparent electrode forming step. Set the value equal to the amount of expansion / contraction of the board. This can prevent misalignment (alignment misalignment) due to expansion and contraction of the substrate due to the thermal process when forming a color filter layer or a transparent electrode on the reflective electrode, and at the same time increase the effective pixel area. it can.
[0160]
【The invention's effect】
As described above, the liquid crystal display device of the present invention is formed on the reflective electrode formed on the upper side of the substrate, the color filter layer formed on the reflective electrode, the upper side of the color filter layer, and the The transparent electrode electrically connected with the said reflective electrode is provided in the peripheral part of a color filter layer.
[0161]
In addition, as described above, the manufacturing method of the liquid crystal display device according to the present invention forms the reflective electrode on the upper side of the substrate, forms a color filter layer on the reflective electrode, and forms the above-mentioned at the peripheral portion of the color filter layer. In this method, a transparent electrode is formed above the color filter layer so as to be electrically connected to the reflective electrode.
[0162]
According to the said structure, a reflective electrode and a transparent electrode are electrically connected in the peripheral part of a color filter layer. Therefore, even if a positional shift occurs due to the expansion and contraction of the substrate in the color filter layer forming step, the electrical connection between the reflective electrode and the transparent electrode can be ensured.
[0163]
As a result, a liquid crystal display device that can achieve a reduction in weight, an improvement in impact resistance, and a reduction in cost by using a plastic substrate as a substrate, and can prevent deterioration in display image quality due to expansion and contraction of the substrate. There is an effect that it can be provided.
[0164]
In the liquid crystal display device of the present invention, as described above, the distance from the side edge of the reflective electrode to the side edge of the color filter layer is determined based on the amount of expansion and contraction of the substrate in the process of forming the color filter layer and the transparent electrode. It is what.
[0165]
In addition, as described above, the method for manufacturing a liquid crystal display device according to the present invention is based on the distance from the side edge of the reflective electrode to the side edge of the color filter layer, and the amount of expansion / contraction of the substrate in the step of forming the color filter layer and the transparent electrode It is a method to decide based on.
[0166]
According to the above configuration, even when a plastic substrate is used as the substrate, the distance from the side edge of the reflective electrode to the side edge of the color filter layer is the amount of positional deviation between the reflective electrode and the color filter layer due to the expansion and contraction of the substrate. Further, it can be set larger than the amount of positional deviation between the reflective electrode and the transparent electrode. That is, the color filter layer can be accurately aligned on the reflective electrode. Therefore, it is possible to prevent the positional deviation between the reflective electrode and the color filter layer and the positional deviation between the reflective electrode and the transparent electrode.
[0167]
Thereby, there is an effect that it is possible to realize weight reduction, improvement in impact resistance, and cost reduction by using a plastic substrate as the substrate. Furthermore, there is an effect that it is possible to provide a liquid crystal display device capable of preventing deterioration of display image quality due to expansion and contraction of the substrate.
[0168]
In addition, as described above, the liquid crystal display device of the present invention has a plurality of pixels arranged in a matrix in the liquid crystal display device having the above-described configuration, and a plurality of the reflective electrodes correspond to the plurality of pixels. The color filter layer is formed so as to overlap with a plurality of adjacent reflective electrodes in the row direction or the column direction of the plurality of pixels.
[0169]
Alternatively, in the liquid crystal display device of the present invention, as described above, in the liquid crystal display device having the above-described configuration, a plurality of the reflective electrodes are formed in a matrix on the upper side of the substrate, and the color filter layer is The reflective electrode matrix is formed so as to cover a plurality of reflective electrodes adjacent in the row direction or column direction.
[0170]
According to the said structure, the reflective electrode of many areas can be covered with a color filter layer. Therefore, the effective pixel area of the pixel electrode composed of the reflective electrode and the transparent electrode can be increased.
[0171]
Thereby, the effect that the quality of a display image can be improved more is produced.
[0172]
As described above, the liquid crystal display device of the present invention is such that the color filter layer is formed on the reflective electrode in a pattern smaller than the reflective electrode.
[0173]
According to the above configuration, the color filter layer is formed on the reflective electrode in a pattern smaller than the reflective electrode. Therefore, the reflective electrode and the transparent electrode can be patterned with the same mask.
[0174]
As a result, the manufacturing cost of the liquid crystal display device can be reduced.
[0175]
Further, as described above, the liquid crystal display device of the present invention is a liquid crystal display device having the above-described configuration, in which the substrate is a plastic substrate.
[0176]
According to the above configuration, it is possible to prevent displacement due to expansion and contraction of the plastic substrate due to moisture or a heat process when the color filter layer is formed on the reflective electrode on the plastic substrate. Therefore, there is an effect that a liquid crystal display device having no color blur can be realized.
[0177]
The manufacturing method of the liquid crystal display device of the present invention is a method of patterning the reflective electrode and the transparent electrode with the same mask in the manufacturing method of the liquid crystal display device having the above configuration.
[0178]
According to the above configuration, the reflective electrode and the transparent electrode are patterned using the same mask. As a result, the manufacturing cost of the liquid crystal display device can be reduced.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of a liquid crystal display device according to the present invention.
FIG. 2 is a plan view of the liquid crystal display device of FIG.
3A is a plan view showing a state in which the color filter layer extends over a plurality of reflective electrodes in the liquid crystal display device of FIG. 1, and FIG. 3B is a plan view showing the reflective electrodes in the liquid crystal display device of FIG. It is a top view which shows the state patterned only in the direction where a gate wiring is arrange | positioned.
4 is a plan view showing a state in which a color filter layer is formed with a dot pattern smaller than a pixel electrode in the liquid crystal display device of FIG. 1. FIG.
FIG. 5 is a cross-sectional view showing another embodiment of a liquid crystal display device according to the present invention.
6 is a plan view of the liquid crystal display device of FIG.
7A to 7D are diagrams illustrating a process of forming a color filter layer in the liquid crystal display device of FIG.
8A to 8D are diagrams showing a process of forming a transparent electrode in the liquid crystal display device of FIG.
[Explanation of symbols]
2 Plastic substrate (substrate)
13 Reflective electrode
14 Color filter layer
15 Transparent electrode

Claims (6)

An active matrix type liquid crystal display device,
A reflective electrode formed on the upper side of the plastic substrate; a color filter layer formed on the reflective electrode; and an electrode formed on the upper side of the color filter layer and electrically connected to the reflective electrode at a peripheral portion of the color filter layer. Transparent electrodes connected to each other ,
The step of forming the color filter layer and the transparent electrode such that the distance from the side edge of the reflective electrode to the side edge of the color filter layer is such that the width of the color filter layer is smaller than the width of the reflective electrode. a liquid crystal display device comprising that you have determined based on the amount of expansion or contraction of the plastic substrate in the. Having a plurality of pixels arranged in a matrix,
A plurality of the reflective electrodes are formed corresponding to the plurality of pixels,
The liquid crystal display device according to claim 1, wherein the color filter layer is formed so as to overlap with a plurality of reflective electrodes adjacent in the row direction or the column direction of the plurality of pixels. A plurality of the reflective electrodes are formed in a matrix on the upper side of the plastic substrate,
The color filter layer, the liquid crystal display device according to claim 1 or 2, characterized in that it is formed to cover the plurality of reflective electrodes adjacent in the row direction or the column direction in the matrix of the reflective electrode. The color filter layer, the liquid crystal display device according to any one of claims 1, characterized in that it is formed on the reflective electrode pattern smaller than the reflective electrode 3. A reflective electrode is formed on the upper side of the plastic substrate, a color filter layer is formed on the reflective electrode, and the transparent electrode is electrically connected to the reflective electrode at the periphery of the color filter layer. of you formed above, a method for manufacturing an active matrix type liquid crystal display device,
The step of forming the color filter layer and the transparent electrode such that the distance from the side edge of the reflective electrode to the side edge of the color filter layer is such that the width of the color filter layer is smaller than the width of the reflective electrode. method of manufacturing a liquid crystal display device which is characterized that you have determined based on the amount of expansion or contraction of the plastic substrate in the. 6. The method of manufacturing a liquid crystal display device according to claim 5 , wherein the reflective electrode and the transparent electrode are patterned using the same mask.

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